Step 1: What you need

Step 2: Take off the keys!

Unplug your keyboard. I don't think anything bad will happen if you don't, but still. Better safe than sorry.

Take your flathead screwdriver (or similarly shaped tool), and stick it under one of the corners of the key. It helps if you have a part of the screwdriver touching the edge of the "pit" in the keyboard. Cover the area with your hand, so that the key doesn't go flying. Now just push down on the screwdriver, using it kind of like a lever.

Done?

Congratulations! Now just repeat it over 100 times for the rest of your keyboard. Make sure that you organize your keys, so that when you put them back, they're in the right spot. I recommend you do 1 section at a time, so there's less to keep track of. If you do manage to mix them up, here's a good image to use to put them back: http://en.wikipedia.org/wiki/File:Qwerty.svg

Note: I'm only demonstrating on the number pad area of my keyboard because I recently cleaned it. However, the steps are still the same.

Step 3: Clean it!

First, take your keyboard to a garbage can, and shake. Let the solid particles fall into the garbage can. (I actually felt slightly sick at this step.)

Now take a cotton swab, and soak it with the rubbing alcohol. Clean everything out. Rub the key, and then rub the pit. This should dis-infect and clean them both. Now rub the gunk off onto the paper. Don't worry about the alcohol getting inside the keyboard, it evaporates really quickly.